The reduced cigarette sidestream smoke papers or wrappers, as described in U.S. Pat. Nos. 4,231,377 Cline et al.; 4,420,002 Cline; 4,433,697 Cline et al.; 4,450,847, Owens; and 4,881,447 Martin use high levels of basic fillers [MgO/Mg(OH).sub.2 and CaCO.sub.3 ] to achieve reductions in the sidestream smoke of smoking articles. The filler concentrations in these papers are typically in the range of 14 to 60 grams per square meter, which is significantly higher than the 6 to 9 grams per square meter in regular cigarette paper. The high basis weights of these reduced sidestream smoke wrappers (typically 35 to 100 g/m.sup.2) and the resultant thickness increase, along with the "heat sink" effect caused by the thermal breakdown of magnesium hydroxide (shown in equation 1 below), cause an increased condensation of the smoke on the inside surface of the paper and within the paper structure itself. This smoke normally would penetrate through regular cigarette paper and form the typical sidestream smoke plume observed with regular smoking articles. ##STR1##
The increased tar condensation on the inside surface of the cigarette paper and in the internal structure of the cigarette paper itself, along with the significantly higher level of basic fillers [MgO/Mg (OH).sub.2 and CaCO.sub.3 ] in the reduced cigarette sidestream smoke papers, results in a greater reaction of acidic smoke components with the basic fillers in the reduced sidestream smoke papers versus regular cigarette papers. This reaction results in nonvolatile tar components being formed which are not revolatilized back into the mainstream smoke but are pyrolyzed to lower molecular weight smoke components.
Extensive subjective taste studies have shown the taste characteristics of smoking articles wrapped in reduced sidestream smoke papers to have objectional taste characteristics relative to regular smoking articles. Additional studies have also shown the pH of the mainstream smoke of tobacco columns wrapped in reduced sidestream smoke cigarette paper is higher than that of the same tobacco columns wrapped in regular cigarette paper. The subjective taste characteristics of cigarettes wrapped in reduced sidestream smoke cigarette paper are similar to that obtained when the pH of mainstream smoke of regular cigarettes is artificially increased.